Directionally solidified (DS) nickel superalloys are commonly used in turbine blades for high temperature aircraft and space propulsion engines and land-based, high-efficiency power generating plants. Casting of these parts does not always result in perfect crystal grain orientation, which is critical for performance under high temperature conditions. Engine failures, including aircraft mishaps, have heightened the emphasis on efficient and direct measurement of grain orientation in turbine blades.
Conventional chemical etching, visual inspection, and/or laboratory based x-ray analysis techniques based on Laue Diffraction are unsuitable and/or cost prohibitive for quality control of an entire turbine blade. As one example, conventional X-ray Laue Diffraction (XRD) can be used to determine single crystal grain orientation. The conventional approach uses an X-ray area detector to collect an XRD Laue pattern produced by an X-ray beam incident on a sample, and determining the grain orientation by processing this collected Laue pattern. However, certain problems exist when using the Laue method to determine grain orientation for DS blades. DS blades may consist of several, single-crystal grains. Therefore, the diffraction pattern is usually generated from multiple grains and the images become complex and difficult to analyze.
What is required, therefore, are improved techniques for measurement of grain orientation of multiple grain samples.